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Experts Want H.I.V. Testing for All Adults
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Urging a major shift in U.S. policy, some health experts are recommending that virtually all Americans be tested routinely for the AIDS virus, much as they are for cancer and other diseases.
Two multicenter research teams supported in part by the National Institute on Drug Abuse, National Institutes of Health, have independently determined through the development of computer models that routine screening for HIV in health care settings is as cost effective as screening for such other conditions as breast cancer and high blood pressure, and can provide important health and survival benefits. The studies also suggest that screening that leads to a diagnosis of HIV infection may further lower health care costs by preventing high-risk practices and decreasing virus transmission.
Two studies reported in the Feb 10 New England Jnl of Medicine find current testing methods are inadequate & routine HIV testing would: (1) offer survival & CD4 benefits by providing HAART to people identified earlier through routine testing, particularly since a significant proportion of people with HIV are identified or seek care late, with advanced HIV; (2) assist in preventing transmission of HIV; (3) be cost effective; (4) researchers suggest repeated routine testing every 3-5 years.
"...Given the inadequacies of current testing, we believe the case for systematic voluntary HIV screening in health care settings is now compelling... in many health care settings, HIV screening will provide important health benefits for a reasonable investment in health care resources...
... estimated gains in survival and cost-effectiveness for a single HIV test ($38,000 per quality-adjusted life-year gained) compare favorably with other recommended interventions in HIV patient care and many commonly used screening interventions in chronic conditions, including breast cancer, colorectal cancer, diabetes, and hypertension...
... With current practices of HIV detection in the high-risk population, 29 percent of all HIV-infected persons remained undetected until their first opportunistic infection...
... Expanded screening also increased rates of survival...
... Adding a one-time screening with ELISA was associated with earlier diagnosis of HIV, so that the mean CD4 cell count at detection was 210 rather than 154 per cubic millimeter. When repeated testing was introduced, further gains were observed, especially among incident cases. For example, expanding from a single test to screening every five years raised CD4 cell counts at detection among incident cases from 347 to 397 per cubic millimeter and reduced from 27 percent to 16 percent the proportion of cases that were not detected until the patient presented with an opportunistic infection...
... The available evidence strongly indicates that current approaches to testing are inadequate. As noted, AIDS developed in 41 percent of the patients reported in CDC surveillance data within a year after they learned of their HIV-positive status.6 In an ongoing cohort study of veterans, 20 percent of patients had an AIDS-defining illness at presentation for HIV care and 41 percent had a CD4 count of 200 cells per cubic millimeter or less (Justice AC: personal communication). Another study of veterans found that of almost 14,000 patients identified as at risk, only about one third to one half had documentation of HIV testing.178 Together these studies indicate that many patients at risk are not tested at all and that of those who are identified, many have advanced disease...
...When we accounted for changes in risk behavior associated with counseling and the reduction in transmission related to a decreased viral load during HAART, the rates of HIV transmission with the use of screening dropped by slightly more than 20 percent, as compared with no screening. Both changes in behavior and reduced viral load are important mediators of this benefit: HAART would reduce transmission even if patients who screened positive for HIV did not change their risk behavior (a reduction of 12 percent, as compared with no screening). However, the rate of transmission of HIV depends on many factors, including the number of sexual partners, the type and frequency of sex acts, the length of partnerships, the use or nonuse of condoms, and the viral load of the index patient. These factors will vary among populations that are screened, and there is uncertainty about each of them. Nonetheless, the benefit from reduced transmission remained important in our analyses under a broad range of assumptions...
...The main benefit of screening is that people identified as having HIV can begin lifesaving HAART before severe immunologic destruction has occurred. We assumed that, in patients in whom the infection was diagnosed early, HAART would begin when the CD4 count declined to 350 cells per cubic millimeter, the threshold recommended in current treatment guidelines. However, the best time to begin HAART is controversial. The clinical benefit of starting therapy at various CD4 counts has not been evaluated directly in clinical trials. The ongoing Strategies for Management of Antiretroviral Therapy (SMART) study may help determine whether starting treatment when the CD4 count exceeds 350 cells per cubic millimeter and maintaining an undetectable viral load are more clinically beneficial than waiting to start treatment until the CD4 cell count reaches 350 cells per cubic millimeter.177 Our model-based estimates indicate that identifying patients early and beginning therapy when the CD4 count was 350 cells per cubic millimeter, rather than through case finding and beginning therapy when the CD4 count was, on average, 175 cells per cubic millimeter, resulted in a survival advantage of about 1.5 years. This substantial survival advantage is the reason that screening reaches conventional levels of cost-effectiveness even when we did not consider the additional benefit from reduced transmission to sexual partners...
... Our findings are less conclusive with regard to the choice of testing technology. Rapid testing is sensitive to assumptions regarding rates of return, linkage to care, and test specificity. Although sensitivity analysis suggests that the expected costs of false positive results and the reduced quality of life associated with waiting for serologic confirmation are small, a model-based assessment may not adequately capture the range of personal and social distress caused by false positives that could, in rare cases, take months to be recognized.,,,,
...Benefit of Screening Due to Early Identification of HIV: In our base-case analysis, early identification and treatment resulted in an increase in life expectancy of the HIV-infected patient of 1.52 years; the benefit decreased for older patients...
...Benefit of Screening from Reduced Transmission of HIV: Without screening, we estimated that HIV-infected men who have sex with men transmit the virus to 1.12 sexual partners over their lifetime and that heterosexual men and women transmit the virus to 0.42 and 0.14 partner, respectively. If a one-time screening program is implemented...a reduction in the annual transmission rate of approximately 21 percent with the use of a screening strategy, as compared with the absence of screening...
...One-Time Screening: We assessed the cost-effectiveness of screening both with and without considering the benefit to sexual partners. When we considered only the benefit to the identified patient, we found that with an unidentified HIV prevalence of 1 percent, a one-time screening program increased life expectancy by 3.92 days, or 2.92 quality-adjusted days, at a cost of $333 relative to current practice, for an incremental cost-effectiveness of $41,736 per quality-adjusted life-year. Incorporating costs and benefits to partners, we estimated that one-time screening cost $194 more than the cost of current practice, while increasing life expectancy by 5.48 days, or 4.70 quality-adjusted days, for an incremental cost-effectiveness of $15,078 per quality-adjusted life-year...the prevalence of unidentified HIV can be as low as 0.5 percent and still have a cost-effectiveness ratio of less than $50,000 per quality-adjusted life-year, excluding the benefits to partners. Including the costs and benefits to partners, the prevalence of unidentified HIV can be as low as 0.05 percent before it costs $50,000 per quality-adjusted life-year gained..."
Researchers Urge Routine HIV Testing For All Americans
DOW JONES NEWSWIRES
February 9, 2005 5:00 p.m.
TRENTON, N.J. (AP)--Urging a major shift in U.S. policy, some health experts are recommending that virtually all Americans be tested routinely for the AIDS virus, much as they are for cancer and other diseases.
Since the early years of the AIDS epidemic in the 1980s, the government has recommended screening only in big cities, where AIDS rates are high, and among members of high-risk groups, such as gay men and drug addicts.
But two large, federally funded studies found that the cost of routinely testing and treating nearly all adults would be outweighed by a reduction in new infections and the opportunity to start patients on drug cocktails early, when they work best.
"Given the availability of effective therapy and preventive measures, it is possible to improve care and perhaps influence the course of the epidemic through widespread, effective and cost-effective screening," Dr. Samuel A. Bozzette wrote in an editorial accompanying the studies, which appear in Thursday's New England Journal of Medicine.
A failure to institute such screening at doctors' offices and clinics would be "a critical disservice" to patients with the AIDS virus and "the future health of the nation," wrote Bozzette, who is from the University of California at San Diego and the Rand Corp. think tank in Santa Monica, California.
Dr. Robert Janssen, director of HIV-AIDS prevention at the Centers for Disease Control and Prevention, said the CDC will re-evaluate its guidelines over the next two years, and will consider the study's findings as well as the availability of new, rapid HIV tests that produce results in a half-hour instead of the usual week or two.
Who would bear the cost of expanded testing - and the cost of the treatment, which runs to at least $15,000 a year - remains a sticky question amid government cutbacks in health-care funding. However, Janssen said the studies' findings could lead to some private insurers to encourage more HIV testing.
One of the studies, by researchers at Duke and Stanford universities and the Veterans Affairs Palo Alto Health Care System, estimated that routine one-time testing of everyone would cut new infections each year by just over 20%, and that every HIV-infected patient identified would gain an average of 1 1/2 years of life.
The other study, by Yale and Harvard researchers, found that testing people every three to five years would be cost-effective for all but the lowest-risk people, such as those who are celibate or are in monogamous heterosexual relationships. And even for those people, one-time testing was found to be cost-effective.
Nationwide, about 40,000 new HIV infections occur each year. An estimated 950,000 people are infected with the virus, but about 280,000 of them don't know it.
CDC guidelines recommend routine tests wherever the prevalence of HIV infection is more than 1% - basically, cities and some densely populated suburbs.
"If you need proof of the fact that it's not working, look at all the people who have slipped through the cracks - 280,000," said A. David Paltiel of the Yale School of Medicine's division of health policy, lead author of the second study.
The VA-funded study found that in areas where about 1 in 100 patients has undiagnosed HIV - what the CDC calls high-risk settings - widespread testing would cost about $15,100 for each year of good health gained by people diagnosed with the virus, counting the benefits to their sexual partners.
Even in areas with an undiagnosed HIV infection rate of only 1 in 2,000 - the rate in the general population - each healthy year gained by newly diagnosed HIV patients and their partners would still cost less than $50,000. That is the threshold at which health economists generally consider treatments to be cost-effective.
Paltiel noted the two groups of researchers had very similar cost-benefit results, even though they used different computer models.
"The cost-benefit to individuals and society is worth" widespread screening, said Dr. Lawrence Deyton, chief of public health in the Department of Veterans Affairs, which provides medical care to about 5 million veterans.
In light of the findings, he said the VA is going to urge more patients to get tested.
"We're going to take the ball and run with it," Deyton said.
Routine HIV Screening Suggested by US Studies
U.S. Department of Health and Human Services
NATIONAL INSTITUTES OF HEALTH
NIH News
National Institute on Drug Abuse (NIDA)
http://www.nida.nih.gov/
NIDA-FUNDED STUDIES SHOW EXPANDING HIV SCREENING IS COST EFFECTIVE
Two multicenter research teams supported in part by the National Institute on Drug Abuse, National Institutes of Health, have independently determined through the development of computer models that routine screening for HIV in health care settings is as cost effective as screening for such other conditions as breast cancer and high blood pressure, and can provide important health and survival benefits. The studies also suggest that screening that leads to a diagnosis of HIV infection may further lower health care costs by preventing high-risk practices and decreasing virus transmission.
Both studies - one led by Dr. Gillian Sanders at Duke Clinical Research Institute at Duke University and Dr. Douglas Owens at the Veterans Affairs Palo Alto Health Care System; and one led by Dr. A. David Paltiel at Yale School of Medicine - are published in the February 10, 2005 issue of the "New England Journal of Medicine".
"Of the nearly 1 million people in the United States infected with HIV, about 280,000 are unaware of their status," says NIDA Director Dr. Nora D. Volkow. "Current patterns of screening are inconsistent, and people generally are diagnosed late in their disease. There is the possibility that by expanding screening, people identified with HIV can begin highly effective and lifesaving medical therapy early on and improve their quality of life. And, by realizing their HIV status sooner, people may reduce high- risk behaviors and decrease transmission of this virus."
In the first study, the scientists developed a computer model to follow a hypothetical group of 43-year-old men and women whose HIV status was unknown, to estimate the health costs and benefits associated with voluntary HIV screening in health care settings.
"As part of the study, we analyzed the costs associated with HIV testing, counseling, followup, and treatment," says Dr. Sanders. "While no computer model is a perfect representation of reality, the results suggest that a one- time HIV screening program provides a very important health benefit and is a good value, even in populations with a relatively low proportion of people with HIV. In the end, a one-time screening costs about $15,078 for every year of life gained, a figure that takes into account the resulting reduction in virus transmission and benefits to partners."
"An intervention that costs under $20,000 per quality- adjusted life year gained would definitely be recognized as providing good value," notes Dr. Sanders. A quality- adjusted life year is a standard health outcome measure used by many researchers. It is a way to account for both longevity and health-related quality of life.
In addition, the researchers found that implementing a one- time screening program could reduce the annual HIV transmission rate over these patients' lifetimes by 21 percent compared to current practice.
In the second study, researchers developed a computer model that compared costs associated with HIV screening and current voluntary HIV diagnostic and counseling practices in three populations: a "high-risk" population in which 3 percent had undiagnosed HIV infection, a population in which 1 percent had undiagnosed HIV, and the general population in which the prevalence of undiagnosed HIV was 0.1 percent. They found that routine, voluntary HIV screening every 3 to 5 years provides clinical benefits and is cost effective in all but the lowest-risk populations. One-time screening in the general U.S. population also may be cost effective.
"Our study suggests that routine HIV counseling, testing, and referral should be extended," says Dr. Paltiel. "In populations barely meeting a 1 percent prevalence of undiagnosed HIV infection, the costs per quality-adjusted life year gained of HIV testing every 3 to 5 years compare favorably with those of many commonly used screening interventions in chronic conditions, including breast cancer, colorectal cancer, diabetes, and high blood pressure."
Data from other cost-effectiveness studies show that screening for type 2 diabetes costs approximately $56,600 per quality-adjusted life year gained, while screening costs for high blood pressure and colorectal cancer cost $48,000 and $51,200, respectively.
Further research might reveal the best ways to implement HIV screening programs, how to reduce existing barriers to screening, how to increase the effects of counseling on patient knowledge, and the cost-effectiveness of HIV screening in the elderly.
"These studies suggest that voluntary screening for HIV is justified in certain populations and may offer significant benefits on both clinical and cost-effectiveness grounds," says Dr. Volkow. "Additional research is needed to determine if one-time screening for undiagnosed HIV in the general population also is warranted."
The National Institute on Drug Abuse is a component of the National Institutes of Health, U.S. Department of Health and Human Services. NIDA supports more than 85 percent of the world's research on the health aspects of drug abuse and addiction. The Institute carries out a large variety of programs to ensure the rapid dissemination of research information and its implementation in policy and practice. Fact sheets on the health effects of drugs of abuse and information on NIDA research and other activities can be found on the NIDA home page at .
Cost Effectiveness of Screening for HIV, New Studies
Two studies & an editorial were published today in the New England Journal of Medicine & all are reported in this report below.
"...given the availability of effective therapy and preventive measures, it is possible to improve care and perhaps influence the course of the epidemic through widespread, effective, and cost-effective screening...The identification of HIV infection can reduce transmission through two mechanisms: reductions in risk behavior and in infectivity from HAART... In the United States, HIV infection is generally discovered at an advanced stage, usually in the course of medical care and often during care for complications of AIDS...The main benefit of screening is that people identified as having HIV can begin lifesaving HAART before severe immunologic destruction has occurred... The available evidence strongly indicates that current approaches to testing are inadequate. As noted, AIDS developed in 41 percent of the patients reported in CDC surveillance data within a year after they learned of their HIV-positive status... Given the inadequacies of current testing, we believe the case for systematic voluntary HIV screening in health care settings is now compelling... One-time screening in the general population may also be cost-effective... One-time screening improved average survival time among HIV-infected patients...and... was associated with earlier diagnosis of HIV (mean CD4 cell count at diagnosis, 210 vs. 154 per cubic millimeter)..."
NIDA-Funded Studies Show Expanding HIV Screening Is Cost Effective
WASHINGTON, Feb. 9 /PRNewswire/ -- Two multicenter research teams supported in part by the National Institute on Drug Abuse, National Institutes of Health, have independently determined through the development of computer models that routine screening for HIV in health care settings is as cost effective as screening for such other conditions as breast cancer and high blood pressure, and can provide important health and survival benefits. The studies also suggest that screening that leads to a diagnosis of HIV infection may further lower health care costs by preventing high-risk practices and decreasing virus transmission.
Both studies-one led by Dr. Gillian Sanders at Duke Clinical Research Institute at Duke University and Dr. Douglas Owens at the Veterans Affairs Palo Alto Health Care System; and one led by Dr. A. David Paltiel at Yale School of Medicine-are published in the February 10, 2005 issue of the New England Journal of Medicine.
"Of the nearly 1 million people in the United States infected with HIV, about 280,000 are unaware of their status," says NIDA Director Dr. Nora D. Volkow. "Current patterns of screening are inconsistent, and people generally are diagnosed late in their disease. There is the possibility that by expanding screening, people identified with HIV can begin highly effective and lifesaving medical therapy early on and improve their quality of life. And, by realizing their HIV status sooner, people may reduce high-risk behaviors and decrease transmission of this virus."
In the first study, the scientists developed a computer model to follow a hypothetical group of 43-year-old men and women whose HIV status was unknown, to estimate the health costs and benefits associated with voluntary HIV screening in health care settings.
"As part of the study, we analyzed the costs associated with HIV testing, counseling, follow-up, and treatment," says Dr. Sanders. "While no computer model is a perfect representation of reality, the results suggest that a one- time HIV screening program provides a very important health benefit and is a good value, even in populations with a relatively low proportion of people with HIV. In the end, a one-time screening costs about $15,078 for every year of life gained, a figure that takes into account the resulting reduction in virus transmission and benefits to partners."
"An intervention that costs under $20,000 per quality-adjusted life year gained would definitely be recognized as providing good value," notes Dr. Sanders. A quality-adjusted life year is a standard health outcome measure used by many researchers. It is a way to account for both longevity and health-related quality of life.
In addition, the researchers found that implementing a one-time screening program could reduce the annual HIV transmission rate over these patients' lifetimes by 21 percent compared to current practice.
In the second study, researchers developed a computer model that compared costs associated with HIV screening and current voluntary HIV diagnostic and counseling practices in three populations: a "high-risk" population in which 3 percent had undiagnosed HIV infection, a population in which 1 percent had undiagnosed HIV, and the general population in which the prevalence of undiagnosed HIV was 0.1 percent. They found that routine, voluntary HIV screening every 3 to 5 years provides clinical benefits and is cost effective in all but the lowest-risk populations. One-time screening in the general U.S. population also may be cost effective.
"Our study suggests that routine HIV counseling, testing, and referral should be extended," says Dr. Paltiel. "In populations barely meeting a 1 percent prevalence of undiagnosed HIV infection, the costs per quality- adjusted life year gained of HIV testing every 3 to 5 years compare favorably with those of many commonly used screening interventions in chronic conditions, including breast cancer, colorectal cancer, diabetes, and high blood pressure."
Data from other cost-effectiveness studies show that screening for type 2 diabetes costs approximately $56,600 per quality-adjusted life year gained, while screening costs for high blood pressure and colorectal cancer cost $48,000 and $51,200, respectively.
Further research might reveal the best ways to implement HIV screening programs, how to reduce existing barriers to screening, how to increase the effects of counseling on patient knowledge, and the cost-effectiveness of HIV screening in the elderly.
"These studies suggest that voluntary screening for HIV is justified in certain populations and may offer significant benefits on both clinical and cost-effectiveness grounds," says Dr. Volkow. "Additional research is needed to determine if one-time screening for undiagnosed HIV in the general population also is warranted."
The National Institute on Drug Abuse is a component of the National Institutes of Health, U.S. Department of Health and Human Services. NIDA supports more than 85 percent of the world's research on the health aspects of drug abuse and addiction. The Institute carries out a large variety of programs to ensure the rapid dissemination of research information and its implementation in policy and practice. Fact sheets on the health effects of drugs of abuse and information on NIDA research and other activities can be found on the NIDA home page at http://www.drugabuse.gov.
SOURCE National Institute on Drug Abuse
EDITORIAL
Routine Screening for HIV Infection — Timely and Cost-Effective
Samuel A. Bozzette, M.D., Ph.D.
From the RAND Corporation, Santa Monica, Calif., the University of California, San Diego, La Jolla, and the Veterans Affairs San Diego Healthcare System, San Diego.
In the United States, HIV infection is generally discovered at an advanced stage, usually in the course of medical care and often during care for complications of AIDS. Earlier diagnosis would be far preferable, because it could speed access to appropriate care and increase the proportion of HIV-infected patients receiving care, thereby improving the quality of care for persons and populations.1
Two articles in this issue of the Journal indicate that widespread use of routine screening could offer these benefits and more at a reasonable cost. Paltiel and colleagues2 and Sanders and colleagues3 both predict that widespread use of routine screening will yield substantial benefits for HIV-infected patients. Paltiel et al. estimate that the average CD4 count at the detection of HIV infection would rise from 154 to 210 cells per cubic millimeter and that the proportion of cases diagnosed at the time of an opportunistic complication would drop. These factors are important, because earlier access to antiretroviral therapy is likely to make it easier to suppress viral replication, improve immunity, and reduce drug-related adverse effects.4 Consistent with this outcome, both studies estimate that the effects of screening would extend survival by 1.5 years for the average HIV-infected patient.
These gains would come at a reasonable cost. The Centers for Disease Control and Prevention has recommended the routine use of screening in populations with a prevalence of HIV infection of 1 percent or greater. In such a population, Sanders et al. and Paltiel et al. estimate that the cost of one-time screening is $41,736 and $38,000 per quality-adjusted life-year gained, respectively; both estimates are less than the commonly cited threshold for cost-effective care of $50,000 per quality-adjusted life-year gained. Cost-effectiveness changes with the prevalence of disease. Paltiel and colleagues estimate that in high-risk populations (those with a 3 percent prevalence of HIV infection), the costs would decrease to $38,000 per quality-adjusted life-year gained, and in the general U.S. population (which has a 0.1 percent prevalence of HIV infection), the costs would increase to $113,000 per quality-adjusted life-year gained. Repeated testing decreases efficiency, since it detects only incident cases. Given a 3 percent prevalence of HIV infection, Paltiel et al. estimate that testing every five years would cost $50,000 per quality-adjusted life-year gained, and testing every three years would cost $63,000 per quality-adjusted life-year gained. Overall, these results indicate that widespread use of HIV screening is consistent with commonly accepted standards for clinical practice when the prevalence of HIV infection is 1 percent or higher and that testing at five-year intervals may be a reasonable approach in some populations.
Shifting from an individual to a public health perspective, these studies indicate that the benefits of screening extend to society generally. Sanders et al. estimate that routine one-time screening would reduce the annual rate of transmission by slightly more than 20 percent.3 Incorporating this effect on transmission into their model increases survival, lowers overall costs, and dramatically improves the cost-effectiveness of screening from $41,736 to $15,078 per quality-adjusted life-year gained in a population with a 1 percent prevalence of HIV infection. Furthermore, in the analyses that incorporated the effects of screening on transmission, the cost of routine HIV screening did not surpass $50,000 per quality-adjusted life-year gained until the prevalence fell to half that of the general U.S. population, or 0.05 percent.
In keeping with standard practice, these models do not incorporate certain secondary benefits of screening, even though some can be quite important. Preservation of health and reductions in transmission will reduce productivity lost as a result of HIV infection. The averted losses represent savings that, from society's perspective, can partially cancel out the direct expenditures. Because the indirect costs of HIV disease are substantial, the true economic costs of screening are far lower than reflected by direct expenditures. Greater knowledge of infection rates across facilities and regions will improve the allocation of resources to treat and prevent HIV infection. Earlier institution of HIV-prevention measures will help combat the epidemic of other sexually transmitted diseases. Most provocatively, reductions in transmission may appreciably reduce the effective person-to-person transmissibility (known as R) of HIV. If substantial, this effect will increase the likelihood that measures such as a partially effective vaccine will decrease the rate of transmission to less than one new infection per infected person (i.e., R less than 1) and eventually extinguish the epidemic.
The models also do not incorporate certain negative effects of screening. The complexity of screening programs will vary according to type and setting, and operational difficulties could cause the total costs of such programs to exceed those assumed in these studies. The need for counseling of patients will divert clinic staff from other tasks. At some sites, much of this counseling will be for false positive results, even given the low expected rate of only 1 false positive result per 200,000 persons screened in the general population. The strain on clinic budgets and the budgets of certain programs (e.g., the AIDS Drug Assistance Program) will increase. Fear of HIV screening may lead some patients to avoid needed care for other conditions. For these reasons, screening programs should be routine but not mandatory, should pay scrupulous attention to patients' privacy, and should be supported by new resources.
Examining the models used in the two studies provides further insights. Sanders et al. used a Markov model that manipulates fractions of the whole population to track the course of groups of like patients.5 Paltiel et al. used a microsimulation model that evaluates the course of many individual patients and then aggregate the resulting data to the population level.6 The credibility of these authors' conclusions is greatly enhanced by the similarity of findings from the two different models. In their sensitivity analysis, Sanders et al. showed that the effectiveness of preventive measures greatly influences overall cost-effectiveness. Paltiel et al. showed that a 50 percent decrease in access or adherence to antiretroviral therapy leads to a 33 percent increase in cost per quality-adjusted life-year gained and that improving the linkage between testing and care increases the gains in survival without affecting the cost-effectiveness ratio. Overall, these relationships suggest that programs should optimize the linkage between obtaining specimens for testing and delivery of results, entry into appropriate care, access to antiretroviral therapy, and receipt of effective preventive measures.
The findings of Paltiel et al. and Sanders et al. show that, given the availability of effective therapy and preventive measures, it is possible to improve care and perhaps influence the course of the epidemic through widespread, effective, and cost-effective screening. Routine, one-time HIV screening linked to high-quality clinical and preventive services should be instituted, starting in high-prevalence areas. Screening programs should be based in health care settings in order to minimize the complexity and stigma of such programs and to exploit the fact that 81 percent of adults in the United States see health care providers at least annually.7 The use of more aggressive screening programs outside of the clinical setting is justifiable for subpopulations with limited access to care. Such programs will have a relatively high yield but must be designed with great caution to avoid difficulties related to the use of profiling, the stigma of testing, and community acceptance. Repeated screening should be considered for high-risk populations, and its value in other populations should be reassessed after one-time screening programs have been firmly established. Failure to implement widespread routine screening for HIV infection represents a critical disservice to patients who are currently infected, those at risk for infection, and the future health of the nation.
Cost-Effectiveness of Screening for HIV in the Era of Highly Active Antiretroviral Therapy
New England Jnl of Medicine Feb 10, 2005
Gillian D. Sanders, Ph.D., Ahmed M. Bayoumi, M.D., Vandana Sundaram, M.P.H., S. Pinar Bilir, A.B., Christopher P. Neukermans, A.B., Chara E. Rydzak, B.A., Lena R. Douglass, B.S., Laura C. Lazzeroni, Ph.D., Mark Holodniy, M.D., and Douglas K. Owens, M.D.
From Duke Clinical Research Institute, Duke University, Durham, N.C. (G.D.S.); the Center for Primary Care and Outcomes Research, Department of Medicine (G.D.S., V.S., S.P.B., C.P.N., C.E.R., D.K.O.), and the Department of Health Research and Policy (L.C.L., D.K.O.), School of Medicine (M.H.), Stanford University, Stanford, Calif.; the Centre for Research on Inner City Health and Division of General Medicine, St. Michael's Hospital, and the Department of Medicine, University of Toronto — both in Toronto (A.M.B.); and Palo Alto Veterans Affairs Health Care System, Palo Alto, Calif. (V.S., L.R.D., M.H., D.K.O.).
ABSTRACT
Background The costs, benefits, and cost-effectiveness of screening for human immunodeficiency virus (HIV) in health care settings during the era of highly active antiretroviral therapy (HAART) have not been determined.
Methods We developed a Markov model of costs, quality of life, and survival associated with an HIV-screening program as compared with current practice. In both strategies, symptomatic patients were identified through symptom-based case finding. Identified patients started treatment when their CD4 count dropped to 350 cells per cubic millimeter. Disease progression was defined on the basis of CD4 levels and viral load. The likelihood of sexual transmission was based on viral load, knowledge of HIV status, and efficacy of counseling.
Results Given a 1 percent prevalence of unidentified HIV infection, screening increased life expectancy by 5.48 days, or 4.70 quality-adjusted days, at an estimated cost of $194 per screened patient, for a cost-effectiveness ratio of $15,078 per quality-adjusted life-year. Screening cost less than $50,000 per quality-adjusted life-year if the prevalence of unidentified HIV infection exceeded 0.05 percent. Excluding HIV transmission, the cost-effectiveness of screening was $41,736 per quality-adjusted life-year. Screening every five years, as compared with a one-time screening program, cost $57,138 per quality-adjusted life-year, but was more attractive in settings with a high incidence of infection. Our results were sensitive to the efficacy of behavior modification, the benefit of early identification and therapy, and the prevalence and incidence of HIV infection.
Conclusions The cost-effectiveness of routine HIV screening in health care settings, even in relatively low-prevalence populations, is similar to that of commonly accepted interventions, and such programs should be expanded.
Timely identification of human immunodeficiency virus (HIV) infection is critical from both clinical and public health perspectives. A delay in diagnosis until late in the course of HIV infection may be associated with irreversible immunologic damage and related complications. Early identification also provides the opportunity to reduce transmission of HIV through changes in risk behavior.1,2,3 Treatment with highly active antiretroviral therapy (HAART) most likely reduces infectivity4 and may therefore afford an additional public health benefit by further reducing transmission.
Despite these compelling reasons for early identification, the Centers for Disease Control and Prevention (CDC) estimate that up to 20,000 new HIV infections annually can be attributed to people who are unaware of their HIV-positive status. Such people represent up to 280,000 of the approximately 950,000 people infected with HIV in the United States.5 CDC data indicate that in 41 percent of HIV-positive patients, the acquired immunodeficiency syndrome (AIDS) develops within a year after they received the diagnosis,6 suggesting that opportunities for preventing adverse outcomes were missed.
A fundamental strategy of a new CDC initiative to promote early identification of HIV disease is to make voluntary HIV testing a routine part of medical care.7,8 Although we and others previously evaluated the cost-effectiveness of screening,9,10,11,12 these analyses were performed before HAART became available. Because both the costs and the benefits of screening have changed since these analyses were published, the current cost-effectiveness of screening and the settings in which screening is economically attractive remain uncertain. We sought to evaluate the cost-effectiveness of voluntary HIV screening in health care settings and to assess how incorporating the costs and benefits associated with reductions in HIV transmission would influence the cost-effectiveness of a screening program.
Discussion
We evaluated the cost-effectiveness of routine screening for HIV infection in the era of HAART. Our analysis indicates that screening for HIV infection is cost-effective relative to other commonly accepted screening programs and medical treatments,168 even when the prevalence of HIV infection is substantially lower than 1 percent, a prevalence that the CDC has used as general guidance for the initiation of routinely recommended as opposed to targeted screening.8 This finding has potential public health implications in that screening for HIV infection is likely to be cost-effective in a much broader range of health care settings than has previously been recognized. Our analysis also highlights the importance of the public health benefit afforded by the identification of HIV infection. The identification of HIV infection can reduce transmission through two mechanisms: reductions in risk behavior and in infectivity from HAART. When we accounted for these important benefits, the cost-effectiveness of screening for HIV became favorable even at infection prevalences of less than 0.1 percent.
The main benefit of screening is that people identified as having HIV can begin lifesaving HAART before severe immunologic destruction has occurred. We assumed that, in patients in whom the infection was diagnosed early, HAART would begin when the CD4 count declined to 350 cells per cubic millimeter, the threshold recommended in current treatment guidelines. However, the best time to begin HAART is controversial.44,169,170,171,172,173,174,175,176 The clinical benefit of starting therapy at various CD4 counts has not been evaluated directly in clinical trials. The ongoing Strategies for Management of Antiretroviral Therapy (SMART) study may help determine whether starting treatment when the CD4 count exceeds 350 cells per cubic millimeter and maintaining an undetectable viral load are more clinically beneficial than waiting to start treatment until the CD4 cell count reaches 350 cells per cubic millimeter.177 Our model-based estimates indicate that identifying patients early and beginning therapy when the CD4 count was 350 cells per cubic millimeter, rather than through case finding and beginning therapy when the CD4 count was, on average, 175 cells per cubic millimeter, resulted in a survival advantage of about 1.5 years. This substantial survival advantage is the reason that screening reaches conventional levels of cost-effectiveness even when we did not consider the additional benefit from reduced transmission to sexual partners.
When we accounted for changes in risk behavior associated with counseling and the reduction in transmission related to a decreased viral load during HAART, the rates of HIV transmission with the use of screening dropped by slightly more than 20 percent, as compared with no screening. Both changes in behavior and reduced viral load are important mediators of this benefit: HAART would reduce transmission even if patients who screened positive for HIV did not change their risk behavior (a reduction of 12 percent, as compared with no screening). However, the rate of transmission of HIV depends on many factors, including the number of sexual partners, the type and frequency of sex acts, the length of partnerships, the use or nonuse of condoms, and the viral load of the index patient. These factors will vary among populations that are screened, and there is uncertainty about each of them. Nonetheless, the benefit from reduced transmission remained important in our analyses under a broad range of assumptions.
The available evidence strongly indicates that current approaches to testing are inadequate. As noted, AIDS developed in 41 percent of the patients reported in CDC surveillance data within a year after they learned of their HIV-positive status.6 In an ongoing cohort study of veterans, 20 percent of patients had an AIDS-defining illness at presentation for HIV care and 41 percent had a CD4 count of 200 cells per cubic millimeter or less (Justice AC: personal communication). Another study of veterans found that of almost 14,000 patients identified as at risk, only about one third to one half had documentation of HIV testing.178 Together these studies indicate that many patients at risk are not tested at all and that of those who are identified, many have advanced disease.
Given the inadequacies of current testing, we believe the case for systematic voluntary HIV screening in health care settings is now compelling. When implementing screening, providers must decide whether to recommend routine screening for all patients or targeted screening based on risk-behavior assessment. The CDC recommends providers consider the type of setting, prevalence of HIV, and behavioral and clinical HIV risk of individual patients when they are deciding between targeted and routinely recommended screening.8 The guideline suggests that a prevalence of 1 percent can be used as a general threshold for recommending routine (as compared with targeted) screening, but it also notes that routine screening may be recommended at lower prevalences depending on available resources and circumstances. Our findings suggest that routine screening would be cost-effective if the prevalence of undiagnosed HIV infection were as low as 0.05 percent. Although the prevalence of undiagnosed HIV infection is largely unknown, it is likely to reach 0.05 percent in many settings, including urgent care clinics, emergency departments, and some primary care clinics. For example, in a blinded serologic survey, we found that the prevalence of undiagnosed HIV infection ranged from 0.13 percent to 2.9 percent in unselected outpatients at six Department of Veterans Affairs health care systems.179 Outpatient populations are rarely offered routine HIV screening. Because the prevalence of HIV infection in these populations is low, the HIV tests that are used should have very high specificity, ensuring low rates of false positive results.
Our analysis indicated that screening would be more effective than current practice and that the cost-effectiveness of screening is well within the range of that of other commonly accepted health care interventions. In addition, we demonstrated that screening is likely to be cost-effective at a substantially lower prevalence than previously recognized. This finding suggests that in many health care settings, HIV screening will provide important health benefits for a reasonable investment in health care resources.
Expanded Screening for HIV in the United States — An Analysis of Cost-Effectiveness
A. David Paltiel, Ph.D., Milton C. Weinstein, Ph.D., April D. Kimmel, M.Sc., George R. Seage, III, Sc.D., M.P.H., Elena Losina, Ph.D., Hong Zhang, S.M., Kenneth A. Freedberg, M.D., and Rochelle P. Walensky, M.D., M.P.H.
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ABSTRACT
Background Although the Centers for Disease Control and Prevention (CDC) recommend routine HIV counseling, testing, and referral (HIVCTR) in settings with at least a 1 percent prevalence of HIV, roughly 280,000 Americans are unaware of their human immunodeficiency virus (HIV) infection. The effect of expanded screening for HIV is unknown in the era of effective antiretroviral therapy.
Methods We developed a computer simulation model of HIV screening and treatment to compare routine, voluntary HIVCTR with current practice in three target populations: "high-risk" (3.0 percent prevalence of undiagnosed HIV infection; 1.2 percent annual incidence); "CDC threshold" (1.0 percent and 0.12 percent, respectively); and "U.S. general" (0.1 percent and 0.01 percent). Input data were derived from clinical trials and observational cohorts. Outcomes included quality-adjusted survival, cost, and cost-effectiveness.
Results In the high-risk population, the addition of one-time screening for HIV antibodies with an enzyme-linked immunosorbent assay (ELISA) to current practice was associated with earlier diagnosis of HIV (mean CD4 cell count at diagnosis, 210 vs. 154 per cubic millimeter). One-time screening also improved average survival time among HIV-infected patients (quality-adjusted survival, 220.7 months vs. 219.8 months). The incremental cost-effectiveness was $36,000 per quality-adjusted life-year gained. Testing every five years cost $50,000 per quality-adjusted life-year gained, and testing every three years cost $63,000 per quality-adjusted life-year gained. In the CDC threshold population, the cost-effectiveness ratio for one-time screening with ELISA was $38,000 per quality-adjusted life-year gained, whereas testing every five years cost $71,000 per quality-adjusted life-year gained, and testing every three years cost $85,000 per quality-adjusted life-year gained. In the U.S. general population, one-time screening cost $113,000 per quality-adjusted life-year gained.
Conclusions In all but the lowest-risk populations, routine, voluntary screening for HIV once every three to five years is justified on both clinical and cost-effectiveness grounds. One-time screening in the general population may also be cost-effective.
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